The present invention relates to the field of information retrieval. More specifically, it is directed to a system and method for incrementally updating and modifying a keyword index in response to user feedback.
Existing keyword search engines for information repositories typically have two components. The first component may be described as a system for classifying a corpus of documents or other objects, such as images. The result of this process is a set of indices or similar data structures that associate keywords or terms with the documents or other objects. The second component provides a means for a user of the search engine to express a query. This component analyzes the query and uses the data structures provided by the first component to provide a set of objects which are deemed to be relevant to the user""s query.
The classification of the information may be a manual process, in which a human classifies each object. This classification may be done by one or more skilled specialists. Alternatively, it may be done by relatively less skilled individuals, such as the authors or creators of the objects, who select descriptive keywords. In another alternative, the classification of documents may be an automatic process, performed by computing systems and software. This generally uses a variety of means to extract a meaningful description of each object. This includes, for example, analyzing text in the document""s title, abstract, or body, or by automatically detecting patterns in images, and so on.
Whether the classification is manual or automatic, in either case the result is a keyword list with associated data that can be used to retrieve relevant objects for a user query. Again, this is accomplished in existing embodiments by a variety of means. At its simplest, each word or phrase in the keyword list points to a list of objects which were classified by that word or phrase, and that list of objects is returned when the query contains that word or phrase. Many variations of this basic method have been developed, including ranking the returned objects by analytical or statistical properties that are intended to reflect the presumed relevance or importance of the object.
From the viewpoint of the invention described here, these existing methods possess two shortcomings. Firstly, the keywords and terms employed by a user in making a query may not agree with the keywords and terms assigned by the manual and/or automatic classification system, and the search words of different users may differ greatly from one another. Secondly, while the sorts of queries provided by an audience of users may change relatively rapidly in response to current events, changing fashion, and other vagaries of public interest, the classification scheme itself is relatively static and only slowly changing. Because of both these factors, there can be a substantial mismatch between the classification system used to classify objects and that employed by users in making their queries. This is a mismatch that grows with time.
The result of this mismatch is that the search engine may fail to find many of the relevant objects, and more of the objects it does retrieve will be irrelevant to the intended query. Thus the user may frequently fail to find the desired information. In order to provide better search results, new methods are required to update the keyword list and classification scheme used in information retrieval systems.
In one aspect, the present invention provides a method, apparatus and article of manufacture to modify the associations between objects in the database and keywords in the index, based on keywords supplied by the user during a search session. These modified associations keep the classification of objects in the database up to date.
Another aspect of the present invention defines a user session as an interaction of a user expressing a query with a database of objects and associated keywords. The invention provides a method for determining user""s satisfaction with the results of the search.
Other aspects and a better understanding of the invention may be realized by referring to the Detailed Description.